mongodb查询语句有哪些

如果觉得 Mongodb 语句不太好理解，可以和 SQL 语句进行对比，学起来要容易很多。

查询(find)

查询所有结果

select*fromarticle
db.article.find()

指定返回哪些键

selecttitle,authorfromarticle
db.article.find({},{"title":1,"author":1})

where条件

select*fromarticlewheretitle="mongodb"
db.article.find({"title":"mongodb"})

and条件

select*fromarticlewheretitle="mongodb"andauthor="god"
db.article.find({"title":"mongodb","author":"god"})

or条件

select*fromarticlewheretitle="mongodb"orauthor="god"
db.article.find({"$or":[{"title":"mongodb"},{"author":"god"}]})

比较条件

select*fromarticlewhereread>=100;
db.article.find({"read":{"$gt":100}})
>$gt(>)、$gte(>=)、$lt(<)、$lte(<=)
select*fromarticlewhereread>=100andread<=200
db.article.find({"read":{"$gte":100,"lte":200}})

in条件

select*fromarticlewhereauthorin("a","b","c")
db.article.find({"author":{"$in":["a","b","c"]}})

like

select*fromarticlewheretitlelike"%mongodb%"
db.article.find({"title":/mongodb/})

count

selectcount(*)fromarticle
db.article.count()

不等于

select*fromarticlewhereauthor!="a"
db.article.find({"author":{"$ne":"a"}})